The authorities say Omar Mateen pledged allegiance to the Islamic State group before carrying out Sunday’s early-morning rampage at a gay nightclub in Orlando that left 50 dead and more than 50 wounded. It was the worst mass shooting in U.S. history.

Donald J. Trump called once again for a ban on Muslim migration to the U.S.

Earlier, a major Republican donor, Meg Whitman, compared Mr. Trump to Hitler and Mussolini, and the Senate majority leader, Mitch McConnell, left open the possibility of rescinding his endorsement of the candidate.

Bernie Sanders reiterated that he had no intention of leaving the race, but he didn’t explicitly say he would challenge Hillary Clinton for the nomination. The two are scheduled to meet on Tuesday.

The creators of “The Good Wife” have written and produced “BrainDead,” a hybrid of political comedy, thriller, horror and science fiction in which a new congressional staff member discovers that things are even worse in Washington than we thought (10 p.m., CBS).

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That familiarity could play a role in a copyright case involving Led Zeppelin. Two of the band’s founders, Jimmy Page and Robert Plant, are expected to appear in a Los Angeles court on Tuesday to defend themselves against a lawsuit claiming that parts of their 1971 classic “Stairway to Heaven” were copied.

They are accused of stealing the opening sequence from another group’s 1968 instrumental piece, “Taurus.” (Judge for yourself while listening to both.)